Polishing pad, polishing apparatus and method for manufacturing polishing pad

ABSTRACT

The present invention relates to a polishing pad comprising a foaming resin frame and a plurality of auxiliary fiber filaments, and each of the auxiliary fiber filaments is independent and dispersed randomly in the foaming resin frame. The invention also relates to a polishing apparatus and a method for manufacturing the polishing pad.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a polishing pad, a polishing apparatus,and a method for manufacturing the polishing pad.

2. Description of the Related Art

Polishing generally refers to a wear control for a preliminary coarsesurface in a process of chemical mechanical polishing (CMP), which makesthe slurry containing fine particles evenly dispersed on the uppersurface of a polishing pad, and at the same time places a substrateagainst the polishing pad and then rubs the substrate repeatedly with aregular motion. The substrate may be objects such as a semiconductor, astorage medium substrate, an integrated circuit, an LCD flat-panelglass, an optical glass and a photoelectric panel. During the polishingprocess, a polishing pad must be used for polishing the substrate, andthe quality of the polishing pad directly influences the polishingeffect of the substrate.

FIG. 1 shows a schematic view of a polishing apparatus with aconventional polishing pad. The polishing apparatus 1 includes a lowerbase plate 11, a mounting sheet 12, a substrate 13, an upper base plate14, a polishing pad 15 and slurry 16. The lower base plate 11 ispositioned opposite to the upper base plate 14. The mounting sheet 12 isadhered to the lower base plate 11 through an adhesive layer (not shown)and is used for carrying and mounting the substrate 13. The polishingpad 15 is mounted on the upper base plate 14, and faces to the lowerbase plate 11 for polishing the substrate 13.

The operation mode of the polishing apparatus 1 is as follows. First,the substrate 13 is mounted on the mounting sheet 12, and then both theupper and lower base plates 14 and 11 are rotated and the lower baseplate 11 is simultaneously moved downward, such that the polishing pad15 contacts the surface of the substrate 13, and a polishing operationfor the substrate 13 may be performed by continuously supplementing theslurry 16 and using the effect of the polishing pad 15.

FIG. 2 shows a sectional view of a first conventional polishing pad. Thepolishing pad 25 is a non-woven-fabric-type polishing pad comprising aplurality of fiber filaments 251 and a resin 252. A method formanufacturing the polishing pad 25 is using a composite materialincluding the velvet or suede-like fiber filaments 251 and the resin252. The fiber filaments 251 are manufactured by a non-woven producingmethod such as needle felting, cotton carding or cotton folding, and theproduced fiber filaments are intertwined with each other. Then, anon-woven fabrics formed by the fiber filaments 251 are immersed in athermoplastic polyurethane resin 252 to form a softer thin slice havinghigh compressed transformation by wet solidification. However, due tothe softness of the non-woven-fabric-type polishing pad 25, theplanarization of a polishing surface is poor. Furthermore, the hardnessof the polishing pad 25 is not enough, so the polishing pad 25 is notsuitable for coarse polishing, and the life span of the polishing pad 25is short.

FIG. 3 shows a sectional view of a second conventional polishing pad.U.S. Pat. No. 5,578,362 discloses a polishing pad 35 that is anindependent foaming-type polishing pad comprising a plurality of holes353 and a resin 352. A method for manufacturing the polishing pad 35 isfilling the resin 352 (which is usually a foaming polymer formed bythermoplastic polyurethane) into a columnar mold. After cooling andsolidifying, the polishing pad is produced by cutting the resin intoslices. The polishing pad 35 is harder and more wearable than the firstconventional polishing pad 25 (shown in FIG. 2) and has an independentbubble structure, which is often used in high planarization polishing.However, the biggest problem of the polishing pad 35 is that theconcentration of the resin 352 is not easy to be uniformly distributedin the columnar mold. When forming, the differences between thetemperature distributions of each position in the columnar mold causethe various sizes and uneven distribution of the holes 353, and theforming is difficult to be controlled. After slicing process, the holes353 with different sizes of a sliced surface are more obvious. Besides,the holes 353 are not connected to each other and slurry is not easy toflow there between. When polishing, the slurry is unable to infiltrateinto the interior region of the polishing pad, which reduces the slurryretention rate of the surface. In another aspect, due to the highhardness, low heat compression rate, it is easy to scrap the substrateto be polished and the polishing pad 35 is only suitable for coarsepolishing.

Therefore, a novel polishing pad in the field is needed to be developedto overcome the defect of the aforementioned non-woven-fabric-typepolishing pad and independent foaming-type polishing pad and to expandthe scope of its use.

SUMMARY OF THE INVENTION

The present invention is to add a plurality of auxiliary fiber filamentsin an independent foaming-type polishing pad, and the polishing padobtained has high hardness of the independent foaming-type polishingpad. Additionally, the polishing pad has advantages of anon-woven-fabric-type polishing pad such as improving polishinguniformity, and partial elasticity. Furthermore, slurry can alsoinfiltrate into the interior region by the auxiliary fiber filamentswhich can increase the slurry retention rate of the polishing pad.

The present invention provides a polishing pad comprising:

-   -   a foaming resin frame comprising a plurality of holes; and    -   a plurality of auxiliary fiber filaments, wherein each of the        auxiliary fiber filaments is independent and dispersed randomly        in the foaming resin frame.

The present invention also provides a polishing apparatus comprising:

-   -   a polishing plate;    -   a substrate;    -   the aforementioned polishing pad which is adhered on the        polishing plate for polishing the substrate; and    -   a slurry contacting with the substrate for polishing.

The present invention further provides a method for manufacturing theaforementioned polishing pad comprising:

-   -   (a) providing a carrier, wherein the carrier is a releasing        material;    -   (b) providing a foaming resin composition;    -   (c) providing a plurality of auxiliary fiber filaments;    -   (d) randomly dispersing the auxiliary fiber filaments of the        step (c) in the foaming resin composition of the step (b);    -   (e) coating the foaming resin composition randomly dispersed        with the auxiliary fiber filaments of the step (d) on the        carrier of the step (a); and    -   (f) curing the foaming resin composition of the step (e).

The present invention further provides a method for manufacturing theaforementioned polishing pad comprising:

-   -   (a) providing a mold;    -   (b) providing a foaming resin composition;    -   (c) providing a plurality of auxiliary fiber filaments;    -   (d) randomly dispersing the auxiliary fiber filaments of the        step (c) in the foaming resin composition of the step (b);    -   (e) filling the foaming resin composition randomly dispersed        with the auxiliary fiber filaments randomly of the step (d) in a        cavity of the mold (a);    -   (f) curing the foaming resin composition of the step (e); and    -   (g) slicing the cured foaming resin composition of the step (f)        for obtaining the polishing pad.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic view of a polishing apparatus with aconventional polishing pad.

FIG. 2 shows a sectional view of a first conventional polishing pad;

FIG. 3 shows a sectional view of a second conventional polishing pad;

FIG. 4 shows a sectional view of a polishing pad according to thepresent invention; and

FIG. 5 shows a schematic view of a polishing apparatus with a polishingpad according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a polishing pad (shown in FIG. 4)comprising:

-   -   to a foaming resin frame comprising a plurality of holes; and    -   a plurality of auxiliary fiber filaments, wherein each of the        auxiliary fiber filaments is independent and dispersed randomly        in the foaming resin frame.

The term “foaming resin frame” as used herein refers to a main part of apolishing pad which is substantially formed by a foaming resin.

The foaming resin according to the invention is, preferably, anelastomer. As used herein, the term “elastomer,” also known as “elasticpolymer,” refers to a type of polymer that exhibits rubber-likequalities. When polishing, the elastomer serves as a good buffer toavoid scraping a surface of the substrate to be polished. As usedherein, the term “foaming resin” refers to a material containing athermoplastic resin and a thermodecomposing foaming agent. Preferably,the resin comprises at least one selected from the group consisting ofpolyurethane, polyolefin, polycarbonate, polyvinyl alcohol, nylon,elastic rubber, polystyrene, poly aromatic molecules,fluorine-containing polymer, polyimide, crosslinked polyurethane,crosslinked polyolefin, polyether, polyester, polyacrylate, elasticpolyethylene, polytetrafluoroethene, poly (ethylene terephthalate), polyaromatic amide, polyarylalkene, polymethyl methacrylate, a copolymerthereof, a block copolymer thereof, a mixture thereof, and a blendthereof.

A manner of foaming the resin according the invention can be chemicallyfoaming or physically foaming, wherein the chemically foaming manneruses an agent to carry on a chemical reaction to yield gas for beingevenly distributed in the resin composition. Besides, the physicallyfoaming manner comprises infiltrating gas into the resin composition forbeing evenly distributed in the resin composition by stirring.

The foaming resin frame according the invention comprises a plurality ofholes which are formed by foaming. The holes are continuous holes orindependent holes. The term “continuous holes” as used herein refers toat least two holes connecting to each other to form holes similar to antnests. Generally, the continuous holes are formed by chemically foamingThe term “independent holes” as used herein refers to holes which areindependent without connecting to each other, and are similar tobubbles. Generally, the independent holes are formed by physicallyfoaming. Preferably, the holes are independent holes, wherein each of aplurality of holes is independent.

One of technical features according to the invention is to provide aplurality of auxiliary fiber filaments. The term “fiber” as used hereinrefers to a single fiber or composite fiber; preferably, the fiber is acomposite fiber. Artisans skilled in this field can choose the fiberaccording to the material to be polished. Artisans skilled in this fieldcan choose suitable kinds of fibers according to the disclosure of thespecification by coordination the compatibility between the foamingresin frame and fibers. The auxiliary fiber filaments according theinvention have a filamentous structure; preferably, the filamentousstructure is a short filamentous or short rod-like structure. Each ofthe auxiliary fiber filaments is independent which does not form a netstructure, and the auxiliary fiber filaments are not interlaced, alsonot bonded, weaved, knitted, piled or stitched to form a fabric. In onepreferred embodiment of the invention, the length of the auxiliary fiberfilaments is from about 0.1 mm to about 1.0 mm; preferably from about0.2 mm to about 0.8 mm; more preferably from about 0.4 mm to about 0.6mm. In another aspect, the thickness of the auxiliary fiber filaments isfrom about 2 denier to about 5 denier. Preferably the auxiliary fiberfilaments are made of at least one material selected from the groupconsisting of polyamide, terephthalamide, polyester, polymethylmethacrylate, polyethylene terephthalate, and polyacrylonitrile, andmany kinds of materials of the auxiliary fiber filaments can be appliedin the same polishing pad.

A suitable content of the auxiliary fiber filaments according to theinvention can be chosen by the hardness, the removing rate and theslurry retention rate. Preferably, the ratio of the auxiliary fiberfilaments is from about 1% to about 30% by weight; more preferably fromabout 5% to about 20% by weight.

In one preferred embodiment of the invention, a plurality of theauxiliary fiber filaments protrude from a surface of the foaming resinframe, wherein the auxiliary fiber filaments are semi-inlaid orsemi-sunk in the foaming resin frame and semi-exposed on the surface ofa polishing pad which form a structure similar to fluff. The polishingpad according to the embodiment due to the soft auxiliary fiberfilaments protruding on the surface can further reduce the scratcheprobability of a substrate to be polished, and it can also increase theslurry retention rate on the surface of the polishing pad which canpromote the polishing effect.

According to the invention, a plurality of the auxiliary fiber filamentsare added in the polishing pad, preferably in the independentfoaming-type polishing pad which has the advantages of the independentfoaming-type polishing pad such as high hardness. Additionally, thepolishing pad has advantages of the non-woven-fabric-type polishing padsuch as improving polishing uniformity, and partial elasticity.Furthermore, slurry can also infiltrate into the interior region by theauxiliary fiber filaments which can increase the slurry retention rateof the polishing pad

In one preferred embodiment of the invention, the polishing pad furthercomprises a plurality of polishing particles which are dispersedrandomly in the foaming resin frame and can locate in a resin part or ina hole part of the foaming resin frame. Preferably, the polishingparticles comprise cerium dioxide, silicon dioxide, aluminum oxide,yttrium oxide, or ferric oxide. Additionally, the particle diameter ofthe polishing particle is from 0.01 μM to 10 μM.

The invention also provides a polishing apparatus comprising:

-   -   a polishing plate;    -   a substrate;    -   the polishing pad which is adhered on the polishing plate for        polishing the substrate; and    -   a slurry contacting with the substrate for polishing.

Preferably the polishing apparatus further comprising:

-   -   a lower base plate which is positioned opposite to a upper base        plate; and    -   a mounting sheet which is adhered to the lower base plate for        carrying and mounting the substrate.

FIG. 5 shows a schematic view of a polishing apparatus according to thepolishing pad of the invention. The polishing apparatus 5 includes alower base plate 51, a mounting sheet 52, a substrate 53, an upper baseplate 54, a polishing pad 55 and slurry 56. The lower base plate 51 ispositioned opposite to the upper base plate 54. The mounting sheet 52 isadhered to the lower base plate 51 through an adhesive layer (not shown)and is used for carrying and mounting the substrate 53. The polishingpad 55 is mounted on the upper base plate 54, and faces to the lowerbase plate 51 for polishing the substrate 53.

The operation mode of the polishing apparatus 5 is as follows. First,the substrate 53 is mounted on the mounting sheet 52, and then both theupper and lower base plates 54 and 51 are rotated and the lower baseplate 51 is simultaneously moved downward, such that the polishing pad55 contacts the surface of the substrate 53, and the substrate 53 may beperformed by continuously supplementing the slurry 56 and using theeffect of the polishing pad 55.

The present invention also provides a first method for manufacturing theaforementioned polishing pad comprising:

-   -   (a) providing a carrier, wherein the carrier is a releasing        material;    -   (b) providing a foaming resin composition;    -   (c) providing a plurality of auxiliary fiber filaments;    -   (d) randomly dispersing the auxiliary fiber filaments of the        step (c) in the foaming resin composition of the step (b);    -   (e) coating the foaming resin composition randomly dispersed        with the auxiliary fiber filaments of the step (d) on the        carrier of the step (a); and    -   (f) curing the foaming resin composition of the step (e).

The term “carrier” as used herein refers to an element which allows thefoaming resin composition formed thereon and the foaming resincomposition can be easily removed after curing. Preferably, the carrieris a sheet; in another aspect, the carrier is a releasing material. Theterm “releasing material” as used herein refers to a material which doesnot react with the foaming resin composition in the polishing padmanufacturing process and the foaming resin composition can be easilyremoved after the curing. Preferably, the releasing material is “a filmwith low permeability.” The term “film with low permeability” as usedherein refers to a film or thin film that substantially prevents thefoaming resin composition on an upper surface of the film with lowpermeability according to the invention from permeating to a lowersurface of the film with low permeability. In one preferred embodimentof the invention, the film with low permeability can be formed on a basematerial, for example, a paper. Preferably, the carrier comprises apolyethylene glycol terephthalate film, a polypropylene film, apolycarbonate film, a polyethylene film, a polyethylene terephthalatefilm, a releasing paper or a releasing fabric. Additionally, thepreferable polypropylene is oriented polypropylene.

Preferably, the carrier is continuously provided, for example, is arolling releasing material. The rolling releasing material can be usedby roll to roll. Comparing to the conventional manufacture relative tomolding or casting a single polishing pad, the method according to theinvention improves batch uniformity.

In one embodiment of the invention, the foaming resin compositioncomprises a resin, a foaming agent, and a bridging agent.

The term “bridging agent” as used herein refers to an agent that maygenerate a crosslinked reaction with the resin according to theinvention and cure the resin under an appropriate condition. The kind ofthe bridging agent is determined according to the kind of the resin.

The step (d) according to the invention is randomly dispersing theauxiliary fiber filaments of the step (c) in the foaming resincomposition of the step (b). The manner may be chosen by artisansskilled in this field, for example, mixing or stirring together withcomponents of the foaming resin composition to obtain the foaming resincomposition and randomly dispersing the auxiliary fiber filaments in thefoaming resin composition at the same time. In one preferred embodimentof the invention, the steps (b), (c), and (d) can be performed at thesame time.

In one embodiment of the invention, the step (d) comprises bladecoating, printing wheel coating, roll extrusion coating or spraying. Themanner of coating may be chosen by artisans skilled in this field.Besides, the preferred coating is continuously coating.

The method according the invention, the step (f) is curing the foamingresin composition of the step (e). The manner of curing may be chosen byartisans skilled in this field according to the kind of the curing resinand the optional bridging agent. In one preferred embodiment of theinvention, the curing step is curing the foaming resin composition whichhas been dried at a high temperature of 60° C. to 130° C.

In one preferred embodiment of the invention, the method furthercomprises a step (g) of removing the carrier. Preferably, the step ofremoving the carrier is removing the polishing pad from manufacturingequipment after the manufacture method is completed. On the other hand,the step of removing the carrier is removing the carrier from thepolishing pad when polishing. The specific manner of the removingdepends on the carrier, for example, the manner is peeling.

The present invention also provides a second method for manufacturingthe aforementioned polishing pad comprising:

-   -   (a) providing a mold;    -   (b) providing a foaming resin composition;    -   (c) providing a plurality of auxiliary fiber filaments;    -   (d) randomly dispersing the auxiliary fiber filaments of the        step (c) in the foaming resin composition of the step (b);    -   (e) filling the foaming resin composition randomly dispersed        with the auxiliary fiber filaments randomly of the step (d) in a        cavity of the mold (a);    -   (f) curing the foaming resin composition of the step (e); and    -   (g) slicing the cured foaming resin composition of the step (f)        for obtaining the polishing pad.

In the second method for manufacturing the polishing pad, the steps (b),(c), (d), and (f) are practiced in the same manners of theaforementioned first method for manufacturing the polishing pad.

Preferably, in the second method for manufacturing the polishing padaccording to the invention, the mold of the step (a) is a cylindricalmold. The manner may be chosen by artisans skilled in this field. Thestep (e) is to fill the foaming resin composition with the randomlydispersed auxiliary fiber filaments of the step (d) in the cavity of themold of the step (a). The manner may be chosen by artisans skilled inthis field.

The step (g) according to the invention is to slice the cured foamingresin composition of the step (f) for obtaining the polishing pad. Themanner may be chosen by artisans skilled in this field, for example,using a knife to shave a cured resin into slices for manufacturing thepolishing pad.

In one preferred embodiment of the invention, the first or second methodfor manufacturing the polishing pad further comprises a surfacefinishing step, which is finishing a surface of the cured resincomposition. The embodiment of finishing is polishing or shaving a partof the surface. The manner of polishing or shaving the part of thesurface may be chosen by artisans skilled in this field, for example,using sandpaper to polish or a knife to shave; wherein the manners ofthe polishing or shaving are well known to artisans skilled in thisfield.

The following Examples are given for the purpose of illustration onlyand are not intended to limit the scope of the present invention.

EXAMPLE

A resin composition is stirred uniformly and air is infiltrated into theresin composition at a rate of 1000 rpm to 4000 rpm. Then, the resincomposition is coated on a releasing paper with a scraper. The resincomposition is cured at 110° C. for 1 minute, and then dried at 80° C.for 30 seconds in an oven, and the surface is shaved.

While embodiments of the present invention have been illustrated anddescribed, various modifications and improvements can be made by personsskilled in the art. The embodiments of the present invention aretherefore described in an illustrative but not restrictive sense. It isintended that the present invention is not limited to the particularforms as illustrated, and that all the modifications not departing fromthe spirit and scope of the present invention are within the scope asdefined in the appended claims.

What is claimed is:
 1. A polishing pad comprising: a foaming resin framecomprising a plurality of holes; and a plurality of auxiliary fiberfilaments, wherein each of the auxiliary fiber filaments is independentand dispersed randomly in the foaming resin frame.
 2. The polishing padaccording to claim 1, wherein the foaming resin frame comprises at leastone selected from the group consisting of polyurethane, polyolefin,polycarbonate, polyvinyl alcohol, nylon, elastic rubber, polystyrene,polyaromatic molecules, fluorine-containing polymer, polyidmide,cross-linked polyurethane, cross-linked polyolefin, polyether,polyester, polyacrylate, elastic polyethylene, polytetrafluoroethylene,poly(ethylene terephthalate), polyaromatic amide, polyarylalkene,polymethyl methacrylate, a copolymer thereof, a block copolymer thereof,a mixture thereof, and a blend thereof.
 3. The polishing pad accordingto claim 1, wherein each of a plurality of holes is independent.
 4. Thepolishing pad according to claim 1, wherein the length of the auxiliaryfiber filaments is from about 0.1 mm to about 1.0 mm.
 5. The polishingpad according to claim 1, wherein the thickness of the auxiliary fiberfilaments is from about 2 denier to about 5 denier.
 6. The polishing padaccording to claim 1, wherein the ratio of the auxiliary fiber filamentsis from about 1% to about 30% by weight.
 7. The polishing pad accordingto claim 1, wherein the auxiliary fiber filaments are made from at leastone selected from the group consisting of polyamide, p-phenylenediamine,polyester, polymethyl methacrylate, polyethylene terephthalate andpolyacrylonitrile.
 8. The polishing pad according to claim 1, wherein aplurality of the auxiliary fiber filaments protrude from a surface ofthe foaming resin frame.
 9. The polishing pad according to claim 1,wherein further comprises a plurality of polishing particles which aredispersed randomly in the foaming resin frame.
 10. A polishing apparatuscomprising: a polishing plate; a substrate; the polishing pad accordingto claim 1, which is adhered on the polishing plate for polishing thesubstrate; and a slurry contacting with the substrate for polishing. 11.The polishing apparatus according to claim 10, wherein the foaming resinframe comprises at least one selected from the group consisting ofpolyurethane, polyolefin, polycarbonate, polyvinyl alcohol, nylon,elastic rubber, polystyrene, polyaromatic molecules, fluorine-containingpolymer, polyidmide, cross-linked polyurethane, cross-linked polyolefin,polyether, polyester, polyacrylate, elastic polyethylene,polytetrafluoroethylene, poly(ethylene terephthalate), polyaromaticamide, polyarylalkene, polymethyl methacrylate, a copolymer thereof, ablock copolymer thereof, a mixture thereof, and a blend thereof.
 12. Thepolishing apparatus according to claim 10, wherein each of a pluralityof holes is independent.
 13. The polishing apparatus according to claim10, wherein the length of the auxiliary fiber filaments is from about0.1 mm to about 1.0 mm.
 14. The polishing apparatus according to claim10, wherein the thickness of the auxiliary fiber filaments is from about2 denier to about 5 denier.
 15. The polishing apparatus according toclaim 10, wherein the ratio of the auxiliary fiber filaments is fromabout 1% to about 30% by weight.
 16. The polishing apparatus accordingto claim 10, wherein the auxiliary fiber filaments are made from atleast one selected from the group consisting of polyamide,p-phenylenediamine, polyester, polymethyl methacrylate, polyethyleneterephthalate and polyacrylonitrile.
 17. The polishing apparatusaccording to claim 10, wherein a plurality of the auxiliary fiberfilaments protrude from a surface of the foaming resin frame.
 18. Thepolishing apparatus according to claim 10, wherein further comprises aplurality of polishing particles which are dispersed randomly in thefoaming resin frame.
 19. A method for manufacturing the polishing padaccording to claim 1 comprising: (a) providing a carrier, wherein thecarrier is a releasing material; (b) providing a foaming resincomposition; (c) providing a plurality of auxiliary fiber filaments; (d)randomly dispersing the auxiliary fiber filaments of the step (c) in thefoaming resin composition of the step (b); (e) coating the foaming resincomposition randomly dispersed with the auxiliary fiber filaments of thestep (d) on the carrier of the step (a); and (f) curing the foamingresin composition of the step (e).
 20. The method according to claim 19,wherein the carrier comprises a polyethylene glycol terephthalate film,a polypropylene film, a polycarbonate film, a polyethylene film, apolyethylene terephthalate film, a release releasing paper or a releasereleasing fabric.
 21. The method according to claim 19, wherein thecarrier is continuously provided.
 22. A method for manufacturing thepolishing pad according to claim 1 comprising: (a) providing a mold; (b)providing a foaming resin composition; (c) providing a plurality ofauxiliary fiber filaments; (d) randomly dispersing the auxiliary fiberfilaments of the step (c) in the foaming resin composition of the step(b); (e) filling the foaming resin composition randomly dispersed withthe auxiliary fiber filaments randomly of the step (d) in a cavity ofthe mold (a); (f) curing the foaming resin composition of the step (e);and (g) slicing the cured foaming resin composition of the step (f) forobtaining the polishing pad.